One day, younger brother Yuuji accidentally discovers his older brother Kouichi deeply engrossed in giving their mother an oil massage, her massive breasts the center of his attention. Overcome by the warmth and softness beneath his hands, Kouichi loses control, hungrily sucking on their mother's tits. Witnessing the scene, Yuuji feels not only shock but also a rising desire of his own—realizing he wants the same. "I can do it too..." he mutters, heading straight toward his mother's bedroom.